Metal shearing machines

ABSTRACT

A metal-shearing machine including a fixed jaw and a movable jaw the latter being constituted by one arm of a member in the form of a bell-crank lever the other arm of which extends downwardly and is connected to one end of a hydraulic piston and cylinder assembly the other end of which is pivotally connected to structure immediately beneath the fixed jaw.

United States Patent Strawson Dec. 18, 1973 [5 METAL SHEARING MACHINES 3,196,727 7/1965 Pray 83/60] [75] Inventor: Kenneth Horace Straws, 3,279,295 10/1966 Teplitz 83/607 x Grenoside, England FOREIGN PATENTS OR APPLICATIONS [73] Assignee: W. E. Burnand & Son Limited, 946,441 1/1964 Great Britain 183/601 Sheffield, England [22] Filed: Mar. 6, 1972 Primary ExaminerWillie G. Abercrombie Appl. No.: 232,133

[30] Foreign Application Priority Data Mar. l0, l97l Great Britain 6,479/71 [52] US. Cl. 83/601 [5i] Int. Cl B26d 5/12 [58] Field of Search 83/597, 60l, 607

[56] References Cited UNITED STATES PATENTS 44!,532 11/1890 Bruce 83/601 X Attorney-Nichol M. Sandoe et a1.

[57] ABSTRACT A metal-shearing machine including a fixed jaw and a movable jaw the latter being constituted by one arm of a member in the form of a bell-crank lever the other arm of which extends downwardly and is connected to one end of a hydraulic piston and cylinder assembly the other end of which is pivotally connected to structure immediately beneath the fixed jaw.

2 Claims, 2 Drawing Figures METAL SHEARING MACHINES The invention relates to metal shearing machines of the kind provided with a movable jaw pivotally con-. nected to a fixed jaw and has for its object to provide an improvement therein.

In particular, it is an object of the invention to provide a metal-shearing machine of compact and robust construction.

According to the invention, there is provided a metal shearing machine having a pair of jaws pivotally connected together and a hydraulic piston and cylinder assembly for oscillating a movable jaw relative to the other fixed jaw said movable jaw being constituted by one arm ofa member in the form of a bell-crank lever the other depending arm of which is connected to one end of the hydraulic piston and cylinder assembly, the latter being pivotally connected at its other end to the said fixed jaw below the front end thereof at a distance less than the length of said depending arm of the bellcrank so that the axis of the piston and cylinder assembly is tilted upwardly at a slight angle to the fixed jaw to which it is pivotally connected. Preferably, also, a fixed one of the jaws is constituted by a forward part of a frame of the machine. The hydraulic piston and cylinder assembly is preferably disposed in a vertical plane containing the cutting edges of shear blades carried by the jaws.

in order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings of which:

FlG. l is a side view of a forward part of a metal shearing machine embodying the invention, and

FIG. 2 is a view in the direction of arrow 2 in FIG. 1.

Referring now to the drawings, a metal shearing machine includes a frame a forward part of which carries an up-standing blade 12 and constitutes a fixed jaw. The forward part of the frame is provided with a pair of wheels 11 but a rearward part thereof is arranged to rest upon the ground. The machine can thus be trundled into a required position, for example in a scrap yard, when its rearward part has been lifted by a mobile crane or the like.

A movable jaw 14 is pivotally connected to the frame 10 by a substantial pivot 16 and carries a blade 18 which co-operates with the blade 12 to shear articles fed between them as the movable jaw moves downwards. The movable jaw is constituted by one arm of a massive casting or fabrication in the form ofa bellcrank lever, the other depending arm 20 of which extends downwardly within the frame. 7

A hydraulic piston and cylinder assembly 22 is disposed within the frame and extends within the fixed jaw beneath the blade 12 from a fixed pivot 24, to which the cylinder is connected, to a pivot pin 26 at the lower end of the arm 20 by means of which the pistonrod of the piston and cylinder assembly is connected to said arm. The distance from the pivot 26 to the edge of the blade 12 is less than the length of the arm 20, so that the axis of the piston and cylinder assembly is tilted upwardly at a slight angle to the blade 12 as shown inFlG. l. The arrangement is such that as hydraulic fluid is pumped into and then discharged from the hydraulic piston and cylinder assembly, alternately, under the control of valve operating mechanism (not shown), the movable jaw. is causedto oscillate up and down. The

piston and cylinder assembly is disposed in a vertical plane containing the cutting edges of the shear blades so that no twisting moment is applied to the pivot 16 as a shearing operation is carried out.

The location of the hydraulic piston and cylinder assembly within the fixed jaw (or within what may be termed structure immediately adjacent the fixed jaw) beneath the blade 12 with its axis tilted upwardly at a slight angle thereto results in a very compact arrangement and there is the added advantage that the portion of the frame rearwards of a region surrounding the pivot 16 is not subject to any stress resulting from an intensity of pressure of hydraulic fluid within the piston and cylinder assembly. This is so no matter how thick a metal or other item of scrap plate being sheared might be. This is shown diagrammatically in FIG. 1 which shows by means of arrows and chain-dotted lines that the system of forces involved whilst a shearing operation is being carried out is confined to a forward part of the machine. This has enabled the portion of the frame rearwards of a region surrounding the pivot 16 to be of relatively light construction with consequent saving of cost.

It has also been found that there is a further advantage in the reaction to the force exerted by the hydraulic piston and cylinder assembly being taken at a point beneath the fixed blade and adjacent a forward end of the frame, that is to say in the piston and cylinder assembly being pivotally connected to the fixed jaw (or to what may be regarded as structure immediately adjacent said fixed jaw). This is that the force applied to the frame by the hydraulic piston and cylinder assembly tends to oppose deflection of the fixed jaw. In other words, it introduces an upwards component of force at the free end of the lower jaw.

Various modifications may be made without departing from the scope of the invention. For example, although it would doubtless result in; a machine of somewhat top heavy appearance, it would be possible to construct a shearing machine some-what similar to that described above and illustrated in the drawings but with the major elements inverted. That is to say, the lower jaw could have an upstanding arm so that the lower jaw and the arm would then form a bell-crank lever) and the movable jaw could have the hydraulic piston andcylinder assembly disposed within or about it, extending substantially horizontally from an upper end of the upstanding arm. v

What I claim and desire to secure by Letters Patent is:

l. A metal shearing machine comprising a frame, a fixed blade mounted on said frame and constituting the fixed jaw of the machine, a bell crank pivotally mounted on said frame near the rear end of said fixed blade, a movable blade mounted on one arm of said bell crank and constituting the movable jaw of the machine, a hydraulic piston and cylinder assembly having one end pivotally connected to the other arm of said bell crank and having another end pivotally mounted on said frame below the front end of said fixed blade at a distance less than the length of said other arm of said bell crank so that the axis of said piston and cylinder assembly is tilted upwardly at an angle to the said fixed blade, whereby hydraulic force acting to extend the assembly to produce a metal shearing of the jaws produces an upward component of force which resists the tendency for the fixed jaw to be deflected during a shearing operation.

2. A metal shearing machine according to claim 1, in which the hydraulic piston and cylinder assembly lies in a vertical plane which also contains the cutting edges of the blades mounted on said fixed and movable jaws. 

1. A metal shearing machine comprising a frame, a fixed blade mounted on said frame and constituting the fixed jaw of the machine, a bell crank pivotally mounted on said frame near the rear end of said fixed blade, a movable blade mounted on one arm of said bell crank and constituting the movable jaw of the machine, a hydraulic piston and cylinder assembly having one end pivotally connected to the other arm of said bell crank and having another end pivotally mounted on said frame below the front end of said fixed blade at a distance less than the length of said other arm of said bell crank so that the axis of said piston and cylinder assembly is tilted upwardly at an angle to the said fixed blade, whereby hydraulic force acting to extend the assembly to produce a metal shearing of the jaws produces an upward component of force which resists the tendency for the fixed jaw to be deflected during a shearing operation.
 2. A metal shearing machine according to claim 1, in which the hydraulic piston and cylinder assembly lies in a vertical plane which also contains the cutting edges of the blades mounted on said fixed and movable jaws. 